pcwzrd13 has a good point and nothing will be as good as an analogue telephone line in terms of latency for Netlink.

Compression is one factor of latency. Servers used by VoIP companies and VoIP devices themselves also contribute lag.

Though you can minimize the lag by bypassing the VoIP serves with a direct connection and turn off compression in the device, the adapters themselves still create latency and that is unavoidable.

Maybe your right. This is all speculation but perhaps the best way to do this without a phone line is if you could directly connect 2 pi's together online, or to a server wich sole purpose is to be the middleman in that configuration.

So the creators of Yabause Sega Saturn Emulator actually has emulated Netlink over LAN/Internet with their Saturn Emulator. Since he knows how Netlink works I'm wondering if he could provide software for Netlinks to connect to a central server...

They have a contact page, but doesn't appear to have a direct emails listed. I might post something on their message board.

As for contacting the team a good way to do it i guess would to comment in one of their newest topics on their website or maybe over at the sega xtreme forms as i think some of the members of the team are there

I think our best bet to implement this with a ras pi would be to get a hold of that yabuse group. I'm thinking they'd be willing to help get this running on raspi's. Seems like everything we'd need is there however Im not a C++/C Programmer

But this looks very promising Maybe Shu or Kazade can take a look at it eventually

Very interesting. Even if the netlink has been emulated in an emulator, you might have trouble getting it to work with real hardware. An emulator can change the way the virtual hardware works to solve some of the issues (not saying that's what they did, but it's a real possibility), you can't change the way a real saturn/netlink works.